GRIGNARD SYNTHESIS OF PI-CONJUGATED POLY(3-ALKYLTHIOPHENES) - CONTROLLING MOLECULAR-WEIGHTS AND THE NATURE OF TERMINAL UNITS

Poly(3-hexylthiophene) has been polymerized by polycondensation of a reaction mixture consisting of 2,5-diiodo-3-hexylthiophene and mono- and di-Grignard reagents thereof. Molecular weights, molecular weight distributions, and the nature of the terminal units were dependent on the percentage compositions of the polymerization mixture. Terminal thienyl units of the polymers possessed Grignard functionality when the initial mixture consisted largely of the di-Grignard reagent. The addition of H2O, D2O, and I2 to this polymer produced hydrogen-, deuterium-, and iodine-terminated polymer chains, as indicated by H-1 NMR. Both 2- and 5-terminal ring protons could be detected upon conversion of the Grignard termini with water.